/ic/ - Artwork/Critique

question.

i've been drawing casually for maybe five years now, but lately I've been getting serious - my plans for this summer are to advance and work hard.

anyways, should i start with 'fun with a pencil', even though these drawings seem very easy for me, or should i continue on to books about perspective and lighting and such?

i just want to know if it's worth it to go through a book that, as far as i can tell, is useful only for giving new artists drawing mileage.

pic attached of something i've drawn recreationally, but it was a while ago so i like to think i've gotten better since then.